Unestimated child issues causes incoherent dependency scheduling

Issue Summary

When using the Auto-scheduler, unestimated issues under the parent causes it to propose incoherent dates that ignore the dependencies and creates conflict. This is also applicable when estimating with "0".

Steps to Reproduce

1. Create Task1, Task2 with 2 Subtasks and Task3
2. Add the dependencies with Task3 blocking Task2 and Task2 blocking Task1
3. Add an Estimate value to Task1, Task2 and Task3 (excluding the subtasks)
4. Add the start/end dates to each Task making sure that they do not clash

Expected Results

When using the Auto-schedule, the scheduler is expected to provide new start/end dates taken into account the dependencies of the Tasks.

Actual Results

The scheduler completely ignores the dependencies and schedule dates that create depedencyes conflict with lead time.

Workaround

All child issues found under the dependency issues must be estimated.